Cellulose acetate material for playing cards, etc.



SPECIFIC Sept. 1, 1936.

GRAVITY w. BOWKER El AL 2,

IN PIGM TO OBTAIN PROPER COVERING POWER I FILLER, PARTS PER IOO PARTS OFCELLULOSE DERIVATIVE INVENTORS Baum ANDERSEN AND WLIJAH BOWKER PatentedSept. 1, 1936 NHTED STATES PATENT OFFICE OELLULOSE ACETATE MATERIAL FORPLAYING CARDS,-ETO.

Application May 18, 1934, Serial No. 726,238

Claims.

This invention relates to card material such ,as playing cards and thelike and to the method of manufacturing the same, wherein the base orbody of the playing card contains cellulose acetate or other organicderivative of cellulose.

An object of the invention is the economic and expeditious production ofcard materials such as playing cards, having a base containing celluloseacetate, which are opaque, springy or full of life and are of lowspecific gravity. Other objects of the invention will appear from thefollowing detailed drawing and specification.

Playing cards made from cellulosic plastics have been known for manyyears but they never attained commercial success because they were tooheavy, that is, they had a too high specific gravity when madesufliciently opaque. Card material made according to this invention,however, is at least as opaque and light as the ordi-' nary type offilled paper cards and has the further advantage of having more-life orsnap, a property much desired by card players. Further, the cards formedaccording to this invention do not, upon use, wear down or peel toexhibit a fabric material that is soft andabsorbent of liquids, etc. Thecards may be washed without hazard of destroying their opacity or snap.

Playing cards made according to the method of this invention are opaqueand of relatively low specific gravity, have low shrinkagecharacteristics, lie fiat without curling and have a snappy resilientfeel to the touch. A further advantage is that the material iscomparatively free from tendency to generate or retain staticelectricity which is characteristic of the usual cellulosic materials orpaper and linen materials. Being free from the property of maintaining astatic electric charge, the cards do not cause lint and dirt particlesto adhere to themselves.

Heretofore, it has beenimpossible to make an entirely satisfactorycellulose acetate sheet material for use in playing cards. The cardshave either been too heavy, too translucent or have exhibited a strongtendency to shrink and warp and have also lacked that resiliency or snapwhich is such a pleasing factor to the card player.

" We have overcome these difliculties and have produced a card whichappears to be satisfacto in every respect.

According to our invention, we produce a satisfactory cellulosederivative playing card material, which has sufiicient opacity andsufiiciently low specific gravity so as to have a feelto the hand morelike the playing card made from a paper or cloth base, and at the sametime has sufiicient stifiness, resiliency and lack of brittleness toform excellent long lasting cards. Accordingly, the

.card material is necessarily made principally from a cellulose acetatebase with or without a small addition of cellulose nitrate or pyroxylin,and using as the principal pigment a very finely divided titaniumdioxide combined with a plasticizer.

The cellulose acetate, preferably with an acetyl value of between 49 andcalculated as acetic 10 acid, may or may not be mixed with from 5 to 15parts of cellulose nitrate per parts of cellulose acetate. It is highlydesirable to incorporate this small percentage of cellulose nitrate withthe cellulose acetate to obtain card material of 15 low shrinkagecharacteristics and at the same time obtain a material which remainsperfectly fiat under all atmospheric conditions. Such a small additionof cellulose nitrate, although materially enhancing the properties ofthe card ma- 20 terial, influences the specific gravity of the cardmaterial with merely about .02 points raise in specific gravity, sayfrom 1.37 to 1.39. Although we do not claim it absolutely necessary toadd this small amount of cellulose nitrate to the cel-- 25 luloseacetate, we have found it highly desirable in spite of the slightincrease in specific gravity, because of the lower shrinkage and betterflat-' ness obtained and also because it results in the cards having asnappier feel and apparently 30 more resilience to the touch.

'I'o every 100 parts by weight of cellulose acetate and cellulosenitrate, if any cellulose nitrate be used, there may be added from 10 to25 parts by weight of a finely divided titanium dioxide. 35 With thispigmentthere is obtained a maximum opacity, an excellent surface colorand at the same time the low specific gravity. It is preferred to usethe titanium oxide as the only pigment as other pigments used therewithare detri- 40 I mental to the excellent properties of the titaniumdioxide. Small amounts, as compared with the titanium dioxide, of otherpigments may be used to promote in the cards properties other thanopacity. To mix, for the purpose of opacity, 45 titanium oxide withother pigments like zinc oxide and zinc sulphide. there is produced notonly a great increase in specific gravity, but also when s'uflicientquantities have been employed based on 100 parts of the cellulosederivative, of volatile solvents, which may consist of equal parts ofethyl alcohol, acetone and ethyl acetate in which plasticizers have beendissolved is poured over the cellulose derivatives and titanium dioxideand the mixture kneaded say from 1 to 4 hours.

The gelatinized mass may then be filtered under pressure to removeforeign material, after which Y it may be worked on malaxating rollsuntil the conversion of the cellulose derivative and dispersion of thepigment is completed. The material may be taken from the rolls in theform of slabs which may be stacked and pressed under heat into a solidblock form. Sheets of desired thickness may be cut from the block on aplaner 'or sheeting machine which sheets are then seasoned to remove thevolatile solvents. The material may then be heat treated beforefinishing, to remove internal stresses set up in the sheet, by heatingto the softening point.

As plasticizers there may be used any of the high boiling solvents oflow volatility as for example the aryl sulphonamids as para ethyl toluolsulphonamid, the alkyl phthalates as dimethyl phthalates, the dialkyltartrates as dibutyl tar- :trate, the alkoxy esters of polybasic organicacids as diethyoxy ethyl'phthalate, and the polybasic organic acidesters of the mono alkyl ethers of polyhydric alcohols as diethyleneglycol ethyl ether ester of phthalic acid. The plasticizers may be usedeither alone or in combination with others. 'Triphenyl phosphate mayalso be used in quantities up to about 15 parts to 100 parts ofcellulose derivative as a fire retarding agent. The quantity ofplasticizers employed may vary within the limits given, depending uponthe flexibility desired and the quantity of pigment incorporated.

The more titanium dioxide the greater the amount of plasticizer. Theamount of total plasticizer employed may vary from 18 to 40 parts byweight per 100 parts of the cellulose derivative in the finishedproduct. v

The plasticizer should be such that it is held tenaciously by thecellulose ester so as to cause a minimum shrinkage in the finishedmaterial and which will permit a thorough elimination of the volatilesolvents used in the processing with a minimum loss of plasticizer. Itis preferable that the volatile solvents be eliminated to the extentthat the residual solvent content be less than 1% in the finishedmaterial.

To facilitate printing, the seasoned sheets may be given a matt orprinting finish or surface by pressing under heat between surfaceshaving an embossing desired to be transferred to the acetate sheets andthen cooling under pressure, for example, a matt finish may be impartedto the material by passing same between sand blasted steel plates, or alinen finish by placing linen cloth of the desired texture on nip rolls.In place minutes. For a deeper etch stronger caustic solutions andhigher temperatures or longer dipping periods may be employed, as forexample,

10% caustic soda solution at 40 C. for 10 minutes. The conditions may bevaried to give any desired results. The caustic treatment not onlyimproves the printing qualities of the sheet, but also tends to improvethe physical characteristics with respect to resiliency, resistance todistortion, etc. Other alkaline materials may be employed such asammonia, potassium and similar hydroxides.

The card material may be printed and embossed in any suitable mannercustomarily employed in theprintingof cellulosic ester materials. Forplaying cards it is preferable to print the sheets and finish. with aheat and pressure treatment to set the ink. Further to preserve the orsynthetic resin and/or a small amount of a suitable plasticizer likealkyl phthalate, aryl phosphate, etc.

In the drawing is illustrated graphically the tremendous importance thepigment and type of cellulose derivative plays in regard to specificgravity of the playing card material. As ordinate is given specificgravity and, as abscissa, parts of filler. The eight curves representdiflerent formulations as follows; the minimum amount of pigmentrequired to impart the necessary opacity being given.

Compound 1 2 3 '4 5 6 7 8 Cellulose acetate 100 90 100 Pyroxylin l00 100100 10 10 PlasticizeL- 30 30 3D Camphor 27.5 27.5 27.5 Titanium dioxide7. 5 16 7. 5 l5 15 Zinc oxide 8O 30 60 30 The circles on the curvesindicate the pigment concentration needed to obtain suflicient opacityof the playing card material, so that the figures on the playing cardcannot be read through even under adverse conditions, such as when aplayer observes a hand in the position between his eyes and a source ofbright light. Curves I, 2 and 3 represent a material made of a cellulosenitrate base lcontaining zinc oxide, 2-containing zinc oxide andtitanium oxide in ratio 4: 1, and 3-co'ntaining a straight titaniumoxide. Although these figures illustrate the tremendous advantagein-selection of pigments, even the best sample has a specific gravity of1.54 which is too high for a good playing card material.

Curves 4 to 8 inclusive illustrate cellulose acetate base material. Itwill be seen that titanium oxide filled material is the only oneproducing a card having a specific gravity below 1.5 such as is desiredby card players. Curves I and 8 represent examples of playing cardshaving the desired properties. It will be seen that 15 parts of titaniumoxide per 100 parts of cellulose derivative is all the pigment necessaryto give a satisfactory opacity and this results in a card materialhaving a specific gravity far below 1.5.

The following examples of composition for aouaeoa forming card materialhaving specific gravity below 1.5 are given for the purpose ofillustrating the invention and not as limitations.

To either of these formulae is added suflicient low boiling solvent toform the desired working consistency and the same are processed as morefully set out above.

It is, of course, understood that this improved material is not limitedto playing cards, but finds wide application in all cases where a thinmaterial of high degree of opacity and of relative nonshrinking andnon-warping characteristics. are desired. Such applications are inprinting and lithographic work, mathematical and precision instrumentsand for veneering purposes, etc. Any desired color effects may beobtained by adding dyes or pigment colors to the titanium dioxide. ,Thecard material may be finished to any suitable thickness, for example,from .001 of an inch to 0.2 of an inch or greater. For playing cardmaterial, the thickness is preferably between 0.008 to 0.012 inch.

Ifdesired, the cellulose acetate in the above formulations may bereplaced in whole or in part by other organic derivative of cellulose,such as cellulose formate, cellulose propionate, cellulose butyrate orother organic esters of cellulose, or

ethyl, methyl or benzyl cellulose or other cellulose ethers.

It is to be understood that the foregoing detailed description anddrawing are merely given by way of illustration and many alterations maybe made therein without departing from the spirit of our invention.

Having described our invention what we desire to secure by LettersPatent is:

1. Opaque sheet material having a specific gravity of less than 1.5 andcontaining cellulose acetate, cellulose nitrate in such proportion as toinhibit curling, plasticizers for the same, and titanium dioxide.

2. Opaque sheet material having a specific gravity of less than 1.5 andcontaining cellulose acetate, cellulose nitrate in such proportion as toinhibit curling, plasticizers for the same and titanium dioxide in anamount equal to from 10 to 25% based on the weight of the cellulosederivatives present.

3. Opaque sheet material having a specific gravity of less than 1.5 andcontaining -95 parts by weight of cellulose acetate, 5-15 parts byweight of cellulose nitrate whereby curling is inhibited, 25-35 parts byweight of plasticizers for the said cellulose derivatives and 10-25parts by weight of titanium dioxide.

4. A playing card comprising opaque sheet material having a specificgravity of less than 1.5 and containing cellulose acetate, cellulosenitrate in such proportion as to inhibit curling, plasticizers for thesame, and titanium dioxide.

5. A playing card comprising opaque sheet material having a specificgravity of less than 1.5 and containing cellulose acetate, a plasticizertherefore, and titanium dioxide, the surface only of the card beingde-esterified.

' BOWKER.

BJORN ANDERSEN.

